Method of making articles from pulp



May 5, 1925 1,536,566

S. CQOPER METHOD OF MAKING ARTICLES FROM PULP Filed March 14. 1933 Patented May 5, 1925.

UNITED STATES SIMON COOPER, OF BROOKLYN, NEW YORK.

METHOD OF MAKING ARTICLES FROM PULP.

Application filed Harsh 14, 1923. Seria1.No. 625,122.

To all whom it may concern:

Be it known that I, SIMON CoorER, a citizen of the United States, residing at Brooklyn, in the county of Kingsand State of New York, have invented certain new and useful Improvements in Methods of Making Articles from Pulp, of which the following is a specification.

This invention relates to the molding of articles from pulp-like material, the general objects of the invention being to secure proper consistency, strength and uniformity of product and to enable the production of such articles on a practical commercial scale.

In its broad aspects, the invention resides in depositing a layer of pulp-like material within a mold in such a way as to produce the requisite thickness and strength of pulp 2 wall at all points. 'This is usually accom-- plished by causing the pulp mixture to fill the mold gradually and progressively so v.as to lay a non-adhering face against the mold wall. After the mold is filled the deposit continues without. interruption but with an,

increased velocity of the mixture until the desired thickness is attained; and then the excess of pulp mixture in the mold is removed. A further feature of the invention 3 consists in supporting or strengthening certain or all portions of the deposited pulp wall, such as that which covers the roof or top of the mold, during the removal of the excess pulp mixture.

Other features of the invention will appear as the specification proceeds.

The accom anying drawing illustrates in more or less. agrammati'c fashion one practical embodiment of apparatus for carrying out the invention.

In said drawing, Figure 1 is a front elevation of such apparatus; and Figure 2 is a vertical sectional view on an enlarged scale, of the suction or forming chambars. I

In the apparatus shown, the mold is filled by applying suction'to the outside of a porous mold whose interior is in communication with a supply of pulp. For this purpose the mold is located in a suction or vacuum chamber 3, which is connected by suitable piping 4, with a vacuum pump or other suction-producing means 5. A so-called vacuum tank 6 is shown located in this line ofpiping to overcome any pulsations of the pump and to enable a steady draw being exerted on the mold-containing chamber.

A suitable mold is indicated in Figure 2, consisting, as there shown, of a foraminous or porous mold wall 7 in the nature of a screen supported in the desired shape by ribbing 8.- This mold is usually con structed in halves so that it can be opened to remove the molded article therefrom, and the top of the mold, which also is porous in its nature, is shown formed as a separateelement 9 held between the two halves. The mouth or lower end of the mold seats upon a supporting flange 10, on the end of the pulp supply-pipe 11, which is entered through the bottom of the chamber; and a shaping ring 12 is usually also rovided within the mouth of the mold for giving the requisite shape to the mouth of the molded article.

The mold-containing chamber is, in the illustration, made in the form of a bell rest-' ing upon a gasket 13, on the base of the late 14, detachably held to said-base plate y jaws 15, which pass through cut-outs or peripheral recesses 16 in the rimofthe base plate and serve as the bell is partiallyrotated, to clamp the bell'tightly down'on the base plate. This construction provides an air-tight readily detachable joint which enables a quick opening up of the scution chamber for the purpose of removing the molded product. I

17 designates a pulp reservoir into which dips the pulp suppl -tube 11, this reservoir being shown carrie by a lever 18 pivoted at 19 and suitably counterwei hted at 20, so that said reservoir ma be owered out of the range of the supp y-tube 11 durmg certain periods of the operations.

A cut-ofi' valve 21 is inter osed in the connections between the suction chamber and suctionroducing means, also a control valve 22 an a by-pass 23 around sa d control valve, governed by a fine re ulatmg valve, such as a needle valve 24. ultable vacuum indicatin gauges 25 may be provided at the suction chamber and vacuum tank and wherever else desirable.

In operation, the reservoir is supplied with a proper mixture of pulp and llquid and is elevated so that the lower end of the pulp supply-pipe 11 is entirely submerged in the pulp. The cut-oil valve 21 being open and control valve 22 being closed, needle valve 24: is opened sulficiently to cause the suction to be exerted at a ratesuch as to cause the mold to be filled gradually and slowly. As the column rises in the mold and contacts progressively with fresh portions of the porous or gauzelike walls of the mold, the liquid at the top of the column, seeking a level, escapes through the meshes by gravity, and perhaps capillarity, and substantially without forced pressure, and the pulp is depositing on the side walls of the mold; and as the mold becomes entirely filled a similar deposit is being made on the top or roof of the mold. As there is practically no agitation or disturbance in the mold chamber during such deposit, the pulp particles or fibres are properly felted, and are merely laid on to the mold; whereas if the pulp mixture should be violently driven into the mold, the consequent agitation and disturbance would prevent proper felting, and pulp particles would be driven into the farominations ofthe mold, and the stripping of the mold from the article would result in tearing of the article,

As the deposit occurs immediately where the liquid has contacted and is flowing through the pores of the mold, the growth or building up of the facing on the side walls is progressive and continuous. The slow and gradual motion of the li uid through the foraminations of the top piece likewise insures a good facing deposit at this oint, which in the case illustrated, constitutes the bottom portion of the completed bottle or hollow. receptacle.

The entire inner surface of the mold being covered with a slowly laid deposit of pulp, the main control valve 22, is momentarily opened, increasing the suction and producing a strong flow through the mold walls, resulting in a definite thickening of the deposit in accordance with the nature of the pulp mixture, the degree of suction and the length of time during which it acts.

The efifect of the operations described is that with the first gradual pull of the suction, a non-adherin face is laid on the mold walls and a proper y felted deposit begun; then, since the suction is not cut off, but increased to thicken the deposit, the deposit will be properly felted and homogeneous, and not laminated, and of a thickness in accordance with the time and degree of suction and the nature of the mixture.

The suction is next cut oil, either at valve 21 or valves 22-24, and a valve 28 is opened, admitting air at atmospheric pressure to the interior of the mold chamber through pipe 29. A feature here is the admissionof this atmospheric air directly beneath the top, and

absence hence the least-supported portion of the pulp layer, so as to provide a support for the same while the mold is being drained. For this purpose I have shown the free air. pipe 29 as terminating in a funnel-shaped piece 30, which acts to admit a. cushion of air beneath the top portion of the pulp wall to support the same as the excess pulp flows back into the reservoir. By regulating the admission of air at valve 28, it will be seen that. the column of pulp may be caused to descend slowly, thus overcoming any tendency of the deposited pulp wall to collapse as equilibrium in pressure is restored at the opposite sides of the pulp wall,

It will be understood that the vacuum or partial vacuum in the mold chamber is not instantaneously broken by the closing of valves 21 or 22-24 and the opening of valve 28, because the atmospheric air can only reach the outside of the mold by passing through the deposit which lines the interior of the mold. Consequently, a gradually decreasing vacuum continues for a time on the outside of the mold, while at the same time there is atmospheric pressure inside the mold. The gradually decreasing vacuum outside the mold helps the incoming air to hold the de osit against the mold walls while the pup mixture column de scends.

When theexcess pulp has all drained back into the reservoir the connection with the reservoir is broken, as by lowering the reservoir away from the mouth of the pipe 11 and the control valve 22 is opened (the airinlet valve 28 having first been closed), submitting the deposited pulp body to suction which removes free liquid retained in the deposited pulp, and thoroughlymats and compacts the deposit,

After closing the control valve 22, the drain valve 27 may be opened to drain the suction chamber by way of pipe 26, after which the base 14 and hell 3 may be relatively rotated to free the jaws 15 from the flange of the base, whereupon the chamber may be opened and the mold be removed therefrom. lihe formed article may then be removed from the mold for further treatment, or in some cases be left in the moldand treated while in place in the mold. The suction being at all times subject to fine control, it is evident that the process'lends itself to practice by way of automatic machineiy, because when once adjustments as to time and degree of suction, etc., have been made in view of a particular size and thickness of finished article, such adjustments may be maintained provided the character and consistency of the pulp mixture are kept uniform,

()bviously, I donot intend to limit myself to the use of the process with any particular sort of pulp or fibre mixture; l have .in mind any mixture of solids and liquids from which, by my process, a de osit of the more solid particles may be me e.

I claim:

The process of forming articles from pulp-like material which comprises applymg suction to the exterior of a porous mold whose interior is in communication with a body of pulp, and controllingthe 'application of'such suction to cause a filling of the mold at a, predetermined rate, and then ad- Initting air directly at the top of the mold thereby relieving the suction on the interior SIMON COOPER. 

